Caprine arthritic encephalitis virus in goats
Caprine arthritis encephalitis virus (CAEV) is a contagious viral disease of goats.
Caprine arthritis encephalitis virus (CAEV) is a member of the small ruminant lentiviruses (also includes ovine progressive pneumonia virus, or OPPV, of sheep), which may lead to chronic disease of the joints, and on rare occasions, encephalitis in goat kids less than six months of age. Cross-infection of sheep with CAEV and goats with OPPV can occur. The disease is typically spread from mother to kid through the ingestion of colostrum or milk. CAE virus may also be spread among adult goats through contact with body secretions including blood and feces of infected goats. Farms with both sheep and goats should incorporate both species into all prevention and control programs. The arthritic form of the disease is most common in adult goats, while the encephalitic form is most common in kids. CAEV is primarily transmitted to kids via colostrum in the first few feedings after birth or by comingling milk from an infected doe or does and feeding it to kids. Blood (e.g., contaminated instruments such as needles, dehorners, etc., and open wounds) is regarded as the second most common way of disease spread. Contact transmission between adult goats is considered to be rare except during lactation. Approximately 35 percent of infected goats will develop arthritis as a clinical sign during their productive lifetime. Although there is no specific treatment for CAEV, goats may be given supportive care including pain medication and antibiotics for opportunistic bacterial infections. Even with supportive care, the encephalitic form is usually fatal.
CAEV infection and spread may be prevented by purchasing only test-negative animals or maintaining a closed herd and removing kids from infected does immediately after birth. Pasteurized kid rearing methods are the key to eliminating milk and colostrum as a route of entry for CAEV. Heat treating colostrum for 60 minutes to 135oF has been shown to prevent transmission of CAEV to kids. Standard pasteurization of treating milk to 165oF for 15 seconds is recommended for CAEV prevention. Kids should receive only heat-treated colostrum and pasteurized milk or milk replacer if there are infected does or does of unknown status in the herd. Individuals testing positive for the CAE virus should be removed from the herd.
Michigan State University Extension recommends the following to control CAEV infection:
- Prevent perinatal transmission by removing kids at birth without allowing contact with the infected doe.
- Prevent milk-borne transmission with heat treated colostrum and pasteurized milk. Careful attention must be paid to achieving the proper temperatures and times.
- Maintain a testing program for CAEV positive does in the herd.
- Separation of positive animals must be complete.
- Negative animals should be milked first and younger animals should be milked before older animals.
- Limit contact between animals at the time of breeding as the potential for transmission during natural breeding does exist.
- Do not share needles. Tattooing equipment or dehorning instruments should be cleaned when being shared between animals with animals of unknown CAEV status.